The aim of this paper is to explore the relationship between the expressions bon père de famille and bonne mère de famille. The expression bon père de famille refers to the reasonable person standard of the French law and has been recently replaced by the terms raisonnablement, raisonnable and personne raisonable. This paper discusses the historical background of the bon père de famille standard in the French law and presents the analysis of occurrences of both expressions in the corpus of legal texts.